Investigations are proposed to increase our knowledge of the biology of mosquitoes "in their natural environment" and thereby enhance the ability to control them and the diseases they transmit. The studies will constitute an extension of a research program on the natural history of mosquitoes now in its twenty-first year under the aegis of the Florida Division of Health, and with NIH support in the past twelve years via many research grants. Our ultimate objective is not only to make possible a greater effectiveness and efficiency in all types of mosquito-control operations, but to steer these as much as possible into a pest-management approach which gives utmost consideration to habitat and non-target biota. In the five-years of support herein requested great emphasis is to be put on flight potential and orientation of flight toward blood and carbohydrate meals, i.e., basic research on natural attraction and natural attractants. The knowledge thus acquired should hasten the adoption of many new non- pesticidal or species- specific chemical techniques now being explored throughout the world. Another feature of the proposed research is its attempt to broaden our understanding of host-selection, longevity, and dispersal through studies of contributing factors. The knowledge sought is thus designed to elucidate the epidemiology of mosquito-borne diseases, especially the arboviruses. Although the aquatic stages will receive some attention, the bulk of the investigations will concern the ecology, behavior and population dynamics of adult mosquitoes. Pioneering studies will be directed, as in the past, at "Aedes taeniorhynchus, Psorophora confinnis, Culex nigripalpus, and Culiseta melanura", the primary pest and disease-vector species of Florida. But, also as in our previous work, findings of import will quickly be examined in some 8 or 9 genera and some 20 or so other species, including anophelines, sabethines, culicines, and exotic species of special biological interest.